Low flow toilets, if required, would be a local requirement.
Smoke and CO2 alarms are probably required; but cheap.
Most everything that you think might be required, are not; but you do have to DISCLOSE "any material fact which could affect the value of the property".
You may post the Listing As-Is and let the Buyer try to intimidate you into doing repairs.
Repost it for Los Angeles and you should get a response.